Coalitions of the foot are relatively uncommon abnormalities, occurring in approximately 1% of the population. Because the majority are asymptomatic, the actual prevalence is likely higher.1-3 Talocalcaneal and calcaneonavicular are the most common types of coalitions. Coalitions in the forefoot are rare, with only a small number of cases reported in the literature.4-6 This article presents the case of a unilateral symptomatic coalition between the first and second metatarsals in a 12-year-old girl who underwent successful surgical excision.Case Report

A 12-year-old girl presented with several months’ history of intermittent right medial-sided dorsal forefoot pain. The pain produced an occasional limp and was exacerbated by physical activity. The patient reported difficulty with shoe wear, which produced mild roughness and redness of overlying dorsal skin. Mild roughness of the skin was noted over the plantar aspect of the first metatarsal head. There was no history of trauma and no associated symptoms, and medical and developmental history was unremarkable.Figure 1: AP (A), oblique (B), and lateral (C) radiographs of the right foot demonstrating a coalition between the first and second metatarsals Figure 1: AP (A), oblique (B), and lateral (C) radiographs of the right foot demonstrating a coalition between the first and second metatarsals Figure 1: AP (A), oblique (B), and lateral (C) radiographs of the right foot demonstrating a coalition between the first and second metatarsalsFigure 1: AP (A), oblique (B), and lateral (C) radiographs of the right foot demonstrating a coalition between the first and second metatarsals.

On examination of the right foot, the patient had a firm, nontender dorsal medial forefoot mass centered between the first and second metatarsals. While the first metatarsal head was level with the second metatarsal head in the sagittal plane, the metatarsals were rigidly fixed to one another. First metatarsal medial cuneiform motion was reduced compared with the unaffected left foot. Subtalar, ankle, and metatarsophalangeal joint motions were normal. The left foot was normal. Neural examination and gait were normal. Radiographs showed a sizable exostosis appearing to bridge the first and second metatarsals (Figure 1). Magnetic resonance imaging (MRI) demonstrated a synostosis and synchondrosis between the first and second metatarsals (Figure 2).

Indications for excision were foot pain and difficulty with shoe wear. A linear incision was made over the dorsum of the foot between the first and second metatarsals overlying the mass. The extensor hallucis longus and extensor digitorum brevis were retracted medialward. The synchondrosis was exposed extraperiosteally, demonstrating attachments at the distal first metatarsal and proximal second metatarsal (Figure 3). An osteotome was used to divide the bridging bone. The bone edges were smoothed using a rongeur and raspatorium. Intraoperative fluoroscopy demonstrated restoration of the normal first and second metatarsal interspace. An immediate improvement was noted in the motion between the first and second metatarsals, as well as first metatarsal-medial cuneiform motion.

Figure 2: Coronal T1-weighted MRI of the right foot demonstrating a bony (arrow head) and cartilaginous (arrow) coalition between the first and second metatarsals. (Abbreviations: Me, medial cuneiform; Mi, middle cuneiform; 1, first metatarsal; 2, second metatarsal.) Figure 3: Intraoperative exposure of the synostosis extending from the distal first metatarsal to the proximal second metatarsal. Figure 4: Postoperative AP fluoroscopic view of the foot demonstrating resection of the synostosis.

The patient bore weight as tolerated, with crutches as needed, in a below-knee cast for 6 weeks postoperatively. At 6-week follow-up, the incisions had healed well and the foot was pain free with weight bearing. The patient had maintained motion between the first and second metatarsals on examination.DiscussionLeer más...